There are a number of different types of incontinence, one of them being what is known as stress incontinence. Stress incontinence means that urine leakage can occur when stress takes place, for example when the sufferer coughs, sneezes, laughs, jumps or carries heavy items, i.e. when certain muscles are stretched. There can be many causes of stress incontinence, and a great deal of research is being undertaken within the area. One of the causes of stress incontinence can be that the muscles which are meant to hold the urethra in place have become weakened; in principle it could be said that the urethra is poorly fastened or poorly fixed in the body. This means that the urethra can slide out of position especially when it is subjected to an increase in pressure in the abdominal cavity, for example when a person laughs. The bladder is situated in the abdominal cavity, and if it is subjected to increased pressure, the muscles are usually capable of resisting, but this is not the case in stress incontinence.
The result of such stress incontinence as just described leading to leakage of urine can feel relatively violent at the moment it occurs, i.e. relatively large volumes of urine may be passed, even as much as 50 cl in the course of a few seconds. This of course places great demands on incontinence devices and other absorbent articles. One way of solving the problem of stress incontinence leakage is to have what are known as raised leakage barriers (also referred to as standing gathers) on the absorbent article.
The leakage barriers are in most cases positioned inside the leg elastic and in most cases consist of a liquid-impermeable material, for example non-woven fabric, but can also be made of liquid-permeable material. The leakage barriers usually extend in the longitudinal direction with the absorption body and are formed by a web, one longitudinal edge of which is attached to the absorbent article and the other, free end of which is intended to lie against the wearer. The free edge is elastically gathered by means of an elastic thread which is folded into the edge of the web. Examples of absorbent articles with leakage barriers (or what are also referred to as liquid barriers) are described in, for example, WO-A1-9207533, U.S. Pat. No. 4,695,278, U.S. Pat. No. 5,064,489, SE-T3-0264238 and GB-A-2188532.
The problem is of course even greater in the case of absorbent articles without these raised leakage barriers. In these articles, there is in most cases only the leg elastic as a barrier or protection against leakage during these temporary urine discharges. Another way of solving this nature of problem for absorbent articles without raised leakage barriers is to bring about a sufficiently good fit so that no leakage can occur.
A common approach is to attempt to have as rapid admission as possible through the liquid-permeable topsheet to the underlying absorption body. There are, however, physical limitations to how rapidly the admission can take place.
U.S. Pat. No. 5,634,917, Fujioka, describes an absorbent article with a number of different possible leg elastic combinations. In one specific embodiment, a first elastic part runs along the leg cutout and crosses the crotch portion horizontally. In the same way, a second elastic part runs along the opposite leg cutout and crosses the crotch portion horizontally. The first and the second elastic parts describe a “U” and an inverted “U” in a central part of the crotch portion. The first and the second elastic parts are also to be separated from one another by a distance “D” in a central part of the crotch portion (see FIG. 7). Although Fujioka touches on a major problem, the document leaves a number of loose ends with scope for improvement.
WO 96/11657, Kawaguchi, describes an absorbent article of the “shorts” type. The document states that it comprises two inventions which together will solve the problems associated with the article sliding down from the wearer on account of the weight of the motion so that leakage occurs. The invention is also said to solve the problem of good fit and to prevent the article swelling. The solution for this is to have a number of elastic threads in or in proximity to the wetting zone, i.e. in the front part of the article, in combination with having a number of elastic threads in “the body surrounding portion”, i.e. in the waist, in such a manner that the distance between them becomes smaller the closer they come to the waist opening.
Another problem encountered with this type of article is leakage on account of the absorption body being subjected to pressure, for example when the wearer sits or lies down. The urine can then be pressed back out of the absorption body, especially if the urine evacuation has taken place recently and the urine has not had time to spread in the absorption body so that the capacity of the whole absorption body has been utilized. It can also happen that the absorption body is subjected to pressure by the wearer at the moment when urine evacuation takes place. This means that the absorption body can have an instantaneously somewhat deteriorated absorption capacity, which requires some form of compensation.
It is therefore not always sufficient to have a good fit. The documents just mentioned indicate different ways of attempting to solve the problems associated with the fit in order to prevent leakage by creating various elastic patterns. However, a great many unsolved problems remain, and the elastic picture is in no way complete, a good fit does not necessarily mean that a heavy instantaneous urine evacuation can be absorbed by the absorption body, especially if it is subjected to pressure or if it will be subjected to pressure directly after urine evacuation. The documents do not go into the problem of heavy instantaneous urine evacuation which what is known as stress incontinence can give rise to. The optimum solution to the problem should therefore not be only to provide protection for these instantaneous urine evacuations but also to ensure that a good fit is maintained or even improved. It is also to be relatively simple to carry out industrial production and also preferably to give the wearer added value in addition to the solution itself to the problem.